U.S. patent application number 17/437219 was filed with the patent office on 2022-02-17 for decorative sheet.
This patent application is currently assigned to Dai Nippon Printing Co., Ltd.. The applicant listed for this patent is Dai Nippon Printing Co., Ltd.. Invention is credited to Takehiko Hiroshima, Yoshio Okabe, Yoshio Sukegawa.
Application Number | 20220048273 17/437219 |
Document ID | / |
Family ID | |
Filed Date | 2022-02-17 |
United States Patent
Application |
20220048273 |
Kind Code |
A1 |
Hiroshima; Takehiko ; et
al. |
February 17, 2022 |
DECORATIVE SHEET
Abstract
Provided is a decorative sheet having excellent
abrasion-resistance. Also, provided is a decorative sheet capable
of reducing abrasion sound. A decorative sheet is provided with; a
linear irregularity pattern formed by a plurality of groove parts
arranged side by side; and a protrusion pattern that coexists
inside the linear irregularity pattern, is arranged at random
without having any regularity with respect to the linear
irregularity pattern, and is formed to have at least a height equal
to or higher than a height of a protrusion part of the linear
irregularity pattern. The protrusion pattern reinforces the linear
irregularity pattern.
Inventors: |
Hiroshima; Takehiko; (Tokyo,
JP) ; Okabe; Yoshio; (Tokyo, JP) ; Sukegawa;
Yoshio; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Dai Nippon Printing Co., Ltd. |
Tokyo |
|
JP |
|
|
Assignee: |
Dai Nippon Printing Co.,
Ltd.
Tokyo
JP
|
Appl. No.: |
17/437219 |
Filed: |
March 14, 2019 |
PCT Filed: |
March 14, 2019 |
PCT NO: |
PCT/JP2019/010597 |
371 Date: |
September 8, 2021 |
International
Class: |
B32B 3/30 20060101
B32B003/30; B44C 3/02 20060101 B44C003/02 |
Claims
1. A decorative sheet comprising: a linear
recess-and-protrusion-pattern portion having a plurality of grooves
arranged side by side; and protrusion pattern portions that are
located in the linear recess-and-protrusion pattern portion and
randomly arranged with no regularity with respect to the linear
recess-and-protrusion pattern portion in plan view in a direction
normal to a sheet surface, the protrusion pattern portions
protruding at least to a height equal to or greater than that of a
protrusion of the linear recess-and-protrusion pattern portion.
2. The decorative sheet according to claim 1, wherein the linear
recess-and-protrusion pattern portion has grooves arranged at a
pitch of 240 .mu.m or less, and the protrusion pattern portions
each have an area of 0.02 mm.sup.2 or more.
3. The decorative sheet according to claim 1, wherein the linear
recess-and-protrusion pattern portion has protrusions with a height
of 5 .mu.m or more.
4. The decorative sheet according to claim 1, wherein the
protrusion pattern portions each have a height of 20 .mu.m or
more.
5. The decorative sheet according to claim 1, wherein the linear
recess-and-protrusion pattern portion is segmented into closed
regions, and the closed regions include adjacent closed regions
different in groove form.
6. The decorative sheet according to claim 1, further comprising a
smooth pattern portion that is further located in the linear
recess-and-protrusion pattern portion, has a pattern different from
that of the linear recess-and-protrusion pattern portion and that
of the protrusion pattern portions, and has a smooth surface,
wherein the protrusion pattern portions each have a height equal to
or greater than that of the smooth pattern portion.
7. The decorative sheet according to claim 1, comprising: a base
material; a patterned layer provided on the base material; and a
resin layer provided on the patterned layer, wherein the linear
recess-and-protrusion pattern portion and the protrusion pattern
portions are molded in the resin layer.
Description
TECHNICAL FIELD
[0001] The present invention relates to a decorative sheet having a
linear recess-and-protrusion pattern.
BACKGROUND ART
[0002] A decorative sheet having a surface with a linear
recess-and-protrusion fine pattern is known in the conventional art
(see, for example, Patent Document 1). Such a linear
recess-and-protrusion fine pattern produces a gloss-lowering effect
at a certain viewing angle when it is a collection of linear
recesses and protrusions parallel to one another. A combination of
multiple collections of linear recesses and protrusions with an
adjusted thickness of each linear pattern can produce multiple
differences in gloss, and also can provide a dynamic design, which
changes the difference in gloss with the viewing angle, when each
of the collections of linear recesses and protrusions has a
different linear direction. A sheet with such a linear
recess-and-protrusion fine pattern needs to have increased scratch
resistance at its recess-and-protrusion portion. This is because,
when scratched with force, the linear recess-and-protrusion pattern
portion may collapse and change in appearance. In order to improve
the scratch resistance, for example, the linear
recess-and-protrusion pattern may be made thick. However, if it is
made so thick that the scratch resistance is kept at a practical
level, the gloss-lowering effect will be low or the linear recesses
and protrusions will be clearly visible, so that the realistic
design appearance may degrade.
[0003] Moreover, a decorative sheet having a linear
recess-and-protrusion fine pattern sometimes produces unpleasant
frictional noise even when the linear recess-and-protrusion pattern
portion is scratched with such a force that it remains uncollapsed.
A need also exists to reduce such frictional noise. [0004] Patent
Document 1: Japanese Unexamined Utility Model Application,
Publication No. H03-62384
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0005] It is an object of the present invention to provide a
decorative sheet having good scratch resistance. It is another
object of the present invention to provide a decorative sheet
capable of producing less frictional noise.
Means for Solving the Problems
[0006] The present invention provides the following solutions to
the problems. In order to facilitate understanding, ordinal numbers
are assigned to embodiments of the present invention to be
described, but such numbering should not be interpreted as
limitation.
[0007] A first aspect of the invention is directed to a decorative
sheet (1, 1B, 1C, 1D) including: a linear recess-and-protrusion
pattern portion (11) having multiple grooves arranged side by side;
and protrusion pattern portions (13) that are located in the linear
recess-and-protrusion pattern portion (11) and randomly arranged
with no regularity with respect to the linear recess-and-protrusion
pattern portion (11) in plan view in a direction normal to the
sheet surface, the protrusion pattern portions (13) protruding at
least to a height equal to or greater than the height of the
protrusion of the linear recess-and-protrusion pattern portion
(11).
[0008] A second aspect of the invention is directed to the
decorative sheet (1, 1B, 1C, 1D) according to the first aspect of
the invention, wherein the linear recess-and-protrusion pattern
portion (11) has the grooves arranged at pitches of 240 .mu.m or
less, and the protrusion pattern portions (13) each have an area of
0.02 mm.sup.2 or more.
[0009] A third aspect of the invention is directed to the
decorative sheet (1, 1B, 1C, 1D) according to the first or second
aspect of the invention, wherein the linear recess-and-protrusion
pattern portion (11) has protrusions with a height of 5 .mu.m or
more.
[0010] A fourth aspect of the invention is directed to the
decorative sheet (1, 1B, 1C, 1D) according to any one of the first
to third aspects of the invention, wherein the protrusion pattern
portions (13) each have a height of 20 .mu.m or more.
[0011] A fifth aspect of the invention is directed to the
decorative sheet (1, 1B, 1C, 1D) according to any one of the first
to fourth aspects of the invention, wherein the linear
recess-and-protrusion pattern portion (11) is segmented into closed
regions, and the closed regions include adjacent closed regions
different in the form of the groove.
[0012] A sixth aspect of the invention is directed to the
decorative sheet (1, 1B, 1C, 1D) according to any one of the first
to fifth aspects of the invention, further including a smooth
pattern portion (12) that is further located in the linear
recess-and-protrusion pattern portion (11), has a pattern different
from that of the linear recess-and-protrusion pattern portion (11)
and that of the protrusion pattern portions (13), and has a smooth
surface, wherein the protrusion pattern portions (13) each have a
height equal to or greater than the height of the smooth pattern
portion (12).
[0013] A seventh aspect of the invention is directed to the
decorative sheet (1, 1B, 1C, 1D) according to any one of the first
to sixth aspects of the invention, comprising a base material (2),
a patterned layer (3) provided on the base material (2), and a
resin layer (4) provided on the patterned layer (3), wherein the
linear recess-and-protrusion pattern portion (11) and the
protrusion pattern portions (13) are molded in the resin layer
(4).
Effects of the Invention
[0014] The present invention makes it possible to provide a
decorative sheet having good scratch resistance. The present
invention also makes it possible to provide a decorative sheet
capable of producing less frictional noise.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a plan view showing a decorative sheet 1 according
to a first embodiment of the present invention;
[0016] FIG. 2 is a view showing only a linear recess-and-protrusion
pattern portion 11 and a smooth pattern portion 12, excluding
protrusion pattern portions 13, among those shown in FIG. 1;
[0017] FIG. 3 is a plan view showing only protrusion pattern
portions 13;
[0018] FIG. 4 is a perspective view showing a portion of the
decorative sheet 1 in an enlarged manner;
[0019] FIG. 5 is a cross-sectional view of the decorative sheet 1
along a cutting plane perpendicular to the sheet surface;
[0020] FIG. 6 is a diagram showing a process of producing the
decorative sheet 1;
[0021] FIG. 7 is a plan view showing pattern No. 3 added for
examination;
[0022] FIG. 8 is a plan view showing pattern No. 4 added for
examination;
[0023] FIG. 9 is a plan view showing pattern No. 7 added for
examination;
[0024] FIG. 10 is a diagram collectively showing what combinations
produced good results, specifically, collectively showing the
results of examination of examples according to the present
invention;
[0025] FIG. 11 is a diagram collectively showing what combinations
failed to produce good results, specifically, collectively showing
the results of examination of comparative examples;
[0026] FIG. 12 is a perspective view showing, in an enlarged
manner, a portion of a decorative sheet 1B according to a second
embodiment of the present invention;
[0027] FIG. 13 is a cross-sectional view of the decorative sheet 1B
along a cutting plane perpendicular to the sheet surface;
[0028] FIG. 14 is a perspective view showing, in an enlarged
manner, a portion of a decorative sheet 1C according to a third
embodiment of the present invention;
[0029] FIG. 15 is a cross-sectional view of the decorative sheet 1C
along a cutting plane perpendicular to the sheet surface;
[0030] FIG. 16 is a perspective view showing, in an enlarged
manner, a portion of a decorative sheet 1D according to a fourth
embodiment of the present invention;
[0031] FIG. 17 is a cross-sectional view of the decorative sheet 1D
along a cutting plane perpendicular to the sheet surface;
[0032] FIG. 18 is a view showing a modified form of the top of
protrusion pattern portions 13; and
[0033] FIG. 19 is a view showing an example of a decorative sheet
also having a recess-and-protrusion pattern on its bottom side.
PREFERRED MODE FOR CARRYING OUT THE INVENTION
[0034] Hereinafter, the best mode for carrying out the present
invention will be described with reference to the drawings.
First Embodiment
[0035] FIG. 1 is a plan view showing a decorative sheet 1 according
to a first embodiment of the present invention. FIG. 2 is a view
showing only a linear recess-and-protrusion pattern portion 11 and
a smooth pattern portion 12, excluding protrusion pattern portions
13, among those shown in FIG. 1. FIG. 3 is a plan view showing only
protrusion pattern portions 13. FIG. 4 is a perspective view
showing a portion of the decorative sheet 1 in an enlarged manner.
FIG. 5 is a cross-sectional view of the decorative sheet 1 along a
cutting plane perpendicular to the sheet surface. The decorative
sheet 1 according to the first embodiment includes a base material
2, a patterned layer 3, and a resin layer 4.
[0036] It should be noted that the drawings referred to below
including FIGS. 1 to 5 are schematic and the size and shape of each
component shown therein are exaggerated as needed to facilitate
understanding. While specific values, shapes, materials, and other
features will be shown in the description below, they may be
altered or modified as needed. Terms used herein to specify shapes
or geometric conditions, such as "parallel" and "perpendicular",
have not only the exact meaning but also other meaning equivalent
in optical function and including errors to such an extent that it
is not considered to depart from the exact meaning, such as
"parallel" or "perpendicular". As used herein, the term "sheet" has
a meaning according to general usage in which "plate", "sheet", and
"film" are used in the order of decreasing thickness. However, such
usage has no technical significance, and these terms may be
interchangeably used as needed. As used herein, the term "sheet
surface" is intended to mean the surface that is oriented in the
plane direction of the sheet when the sheet is viewed as a whole.
For example, referring to FIGS. 1, 2, and 4 shown with the XYZ
coordinate system, the "sheet surface" corresponds to the XY plane
or a plane parallel to the XY plane in each drawing.
[0037] The base material 2 is made of, for example, polyvinyl
chloride resin with a thickness of 300 .mu.m. Besides polyvinyl
chloride resin, the base material 2 may also include, for example,
polyolefin resin, such as polyethylene, polypropylene,
polymethylpentene, polybutene, or olefin-based thermoplastic
elastomer; polyester resin, such as polyethylene terephthalate,
polybutylene terephthalate, polyethylene naphthalate, terephthalic
acid-isophthalic acid-ethylene glycol copolymer, terephthalic
acid-ethylene glycol-1,4 cyclohexanedimethanol copolymer, or
thermoplastic polyester elastomer; polyamide resin, such as nylon
6, nylon 9, or nylon 6,6; polyimide resin; fluororesin, such as
polyvinyl fluoride, polyvinylidene fluoride, polyvinylidene
trifluoride, ethylene-ethylene tetrafluoride copolymer, or
polyethylene tetrafluoride; acrylic resin, polystyrene,
polycarbonate resin, ethylene-propylene copolymer, ethylene-vinyl
acetate copolymer, ethylene-acrylic acid copolymer,
ethylene-propylene-butene copolymer, or thermoplastic polyolefin
elastomer. The acrylic resin may be, for example, one of or a
mixture of two or more of polymethyl (meth)acrylate, polyethyl
(meth)acrylate, polybutyl (meth)acrylate, methyl
(meth)acrylate-butyl (meth)acrylate copolymer, ethyl
(meth)acrylate-butyl (meth)acrylate copolymer, and methyl
(meth)acrylate-styrene copolymer, wherein the term "(meth)acrylate"
means acrylate or methacrylate. The base material may also be paper
or a woven or nonwoven fabric of various fibers having an
appearance and properties similar to those of paper. The various
fibers may include inorganic fibers, such as glass fibers, asbestos
fibers, potassium titanate fibers, alumina fibers, silica fibers,
or carbon fibers, or synthetic resin fibers, such as polyester
fibers, acrylic fibers, or vinylon fibers.
[0038] The patterned layer 3 is a layer having a pattern provided
on one surface of the base material 2. The patterned layer 3 can be
formed, for example, by direct printing on the base material 2.
Besides printing, the patterned layer 3 may be formed by transfer
or the like. In this embodiment, the patterned layer 3 has a
pattern that mimics the appearance of a cut or cleaved surface of a
granite material, which includes different mineral single crystals
arranged in the surface.
[0039] The resin layer 4 is provided on the patterned layer 3 and
made of, for example, polyvinyl chloride resin. Besides polyvinyl
chloride resin, the resin layer 4 may also include, for example,
polyolefin resin, such as polyethylene, polypropylene,
polymethylpentene, polybutene, or olefin-based thermoplastic
elastomer; polyester resin, such as polyethylene terephthalate,
polybutylene terephthalate, polyethylene naphthalate, terephthalic
acid-isophthalic acid-ethylene glycol copolymer, terephthalic
acid-ethylene glycol-1,4 cyclohexanedimethanol copolymer, or
thermoplastic polyester elastomer; polyamide resin, such as nylon
6, nylon 9, or nylon 6,6; polyimide resin; fluororesin, such as
polyvinyl fluoride, polyvinylidene fluoride, polyvinylidene
trifluoride, ethylene-ethylene tetrafluoride copolymer, or
polyethylene tetrafluoride; acrylic resin, polystyrene,
polycarbonate resin, ethylene-propylene copolymer, ethylene-vinyl
acetate copolymer, ethylene-acrylic acid copolymer,
ethylene-propylene-butene copolymer, or thermoplastic polyolefin
elastomer. The resin layer 4 includes transparent or translucent
resin, which allows the pattern of the patterned layer 3 to be seen
through the resin layer 4.
[0040] In the decorative sheet 1 according to this embodiment, the
base material 2, the patterned layer 3, and the resin layer 4 have
a total thickness of, for example, about 20 .mu.m to about 1,000
.mu.m.
[0041] In this embodiment, the resin layer 4 has a surface with a
large number of recess and protrusion geometries. The recess and
protrusion geometries may be broadly classified into three pattern
portions: a linear recess-and-protrusion pattern portion 11, a
smooth pattern portion 12, and a protrusion pattern portion 13.
[0042] As shown in FIGS. 1, 2, and 4, the linear
recess-and-protrusion pattern portion 11 has multiple grooves
arranged side by side, which have a group of parallel straight
lines in plan view, and has a plan view shape (defined later)
including a group of parallel straight lines. In this embodiment,
the linear recess-and-protrusion pattern portion 11 has a large
number of linear grooves arranged side by side. Moreover, the
linear recess-and-protrusion pattern portion 11 is segmented into
closed regions, which include adjacent closed regions different in
the form of grooves. Specifically, one closed region has a certain
groove extending direction, a certain depth, a certain protrusion
width, and a certain groove width, while another closed region
adjacent to the one closed region has a groove extending direction,
a depth, a protrusion width, and a groove width, at least one of
which differs from that of the one closed region. Therefore, each
of the closed regions has a different appearance design.
Furthermore, the area having the linear recess-and-protrusion
pattern portion 11 basically has a matte appearance with low gloss
although it depends on the illumination light incident angle and
the line-of-sight angle.
[0043] The smooth pattern portion 12 is located in the linear
recess-and-protrusion pattern portion 11 and has a pattern
different from those of the linear recess-and-protrusion pattern
portion 11 and the protrusion pattern portion 13. The smooth
pattern portion 12 has a smooth surface. In this embodiment, the
smooth pattern portion 12 has a height equal to the height of the
protrusions of the linear recess-and-protrusion pattern portion 11.
The smooth pattern portion 12 has a smooth surface and has a
somewhat wide area as compared to the area of the protrusion of the
linear recess-and-protrusion pattern portion 11. Therefore, the
smooth pattern portion 12 appears shiny by reflecting light
although it depends on the viewing angle. A combination of the
smooth pattern portion 12 and the linear recess-and-protrusion
pattern portion 11 can provide what is called a gloss and matte
appearance. The term "gross and matte appearance" refers to a
design appearance that is advantageously used to mimic the
appearance of, for example, a cut (or cleaved) surface of a granite
material, which is a mixture of mineral single crystal regions
having a specific composition and having glossy faces with high
gloss and matte faces with low gloss, which appear depending on the
combination of the illumination light incident angle and the
line-of-sight angle. In this regard, the gloss (or matte) of each
of the single crystal regions will change with changing observation
conditions depending on the combination of the illumination light
incident angle and the line-of-sight angle, and the appearance of
the same region will change from glossy to matte or matte to glossy
depending on the observation conditions.
[0044] The protrusion pattern portions 13 are located in the linear
recess-and-protrusion pattern portion 11 and randomly arranged with
no regularity with respect to the linear recess-and-protrusion
pattern portion 11. The protrusion pattern portions 13 each have a
height equal to or greater than the height of the protrusions of
the linear recess-and-protrusion pattern portion 11. As shown in
FIG. 3, the protrusion pattern portions 13 are randomly arranged to
provide a pearskin-like very fine texture as compared to one closed
region of the linear recess-and-protrusion pattern portion 11 and
one closed region of the smooth pattern portion 12. Alternatively,
a specific mode of the protrusion pattern portions 13 may have a
pattern slightly larger than that shown in FIG. 3 (see FIG. 9
referred to later). In this regard, the expression "protrusion
pattern portions 13 randomly arranged" means that all protrusion
pattern portions 13 are arranged such that they neither have plan
view shapes congruent to one another nor are arranged at regular
pitches in a plane in plan view in the direction normal to the
surface of the decorative sheet. All the protrusion pattern
portions 13 on the decorative sheet 1 preferably have two or more
patterns different in plan view shape, and the protrusion pattern
portions 13 adjacent to one another are preferably arranged at two
or more different intervals (pitches) along a plane. More
preferably, all the protrusion pattern portions 13 on the
decorative sheet 1 have different plan view shapes, and each pair
of protrusion pattern portions 13 arranged adjacent to each other
are spaced at a different interval. The term "plan view" regarding
the decorative sheet, each of the pattern portions 11, 12, and 13
on the decorative sheet, and the patterned layer 13 will be
explained with reference to FIGS. 1, 2, and 4 shown with the XYZ
coordinate system. The sheet surface corresponds to the XY plane or
a plane parallel to the XY plane in each drawing, and the direction
normal to the sheet surface corresponds to the Z axis direction.
Therefore, the "plan view" correspond to the appearance of each
decorative sheet, each of the pattern portions 11, 12, and 13, and
the patterned layer 3 as viewed in the Z axis direction. In this
regard, FIG. 1 itself shows the plan view appearance of the
decorative sheet 1.
[0045] The decorative sheet 1 according to this embodiment may be
produced by a process that includes providing a mold having a shape
reverse to that of the decorative sheet 1; and performing molding
using the mold. The decorative sheet 1 may be produced using a
prepared mold. FIG. 6 is a diagram for illustrating a process of
producing the decorative sheet 1. A sheet is provided including a
belt-shaped base material 2 and a patterned layer 3 printed on the
base material 2. The sheet and a polyvinyl chloride resin sheet for
forming a resin layer 4, which is placed on the patterned layer 3
side of the sheet, are fed overlapping each other. The temperature
is adjusted on a large diameter roller 21 and further adjusted by a
heater 22 so that the resin layer 4 is softened while they are fed
to between a die roller 24 and a mold roller 23. While passing
between the die roller 24 and the mold roller 23, the base material
2, the patterned layer 3, and the resin layer 4 are laminated, and
recess-and-protrusion patterns are molded on the resin layer 4, so
that the decorative sheet 1 is completed.
[0046] Next, preferred ranges of the dimensions of each portion of
the decorative sheet 1 will be described. In this regard,
decorative sheets were prepared with a combination of multiple
patterns for the purpose of examining scratch resistance and
frictional noise with respect to a combination of multiple
decorative sheets. FIG. 7 is a plan view showing pattern No. 3
added for the examination. Pattern No. 3 is a modification of
pattern No. 5 shown in FIG. 2 and also includes a linear
recess-and-protrusion pattern portion 11 instead of the smooth
pattern portion 12 of pattern No. 5. FIG. 8 is a plan view showing
pattern No. 4 added for the examination. Pattern No. 4 is a
modification of pattern No. 5 shown in FIG. 2 and includes a
portion having a smooth surface and having a level equal to that of
the grooves of the linear recess-and-protrusion pattern portion 11,
instead of the smooth pattern portion 12 of pattern No. 5. FIG. 9
is a plan view showing pattern No. 7 added for the examination.
Pattern No. 7 is a modification of pattern No. 6 shown in FIG. 3
and includes regions that are arranged in a random pattern as in
pattern No. 6 but each have an area larger than that in pattern No.
6. To facilitate explanation and understanding, patterns Nos. 3, 4,
and 5 are collectively referred to as patterns A, and pattern Nos.
6 and 7 are collectively referred to as patterns B. Patterns B
correspond to the protrusion pattern portions 13. Any one of
patterns A was combined with any one of patterns B. Besides the
combination of patterns, patterns A were provided with different
pitches and different heights, and patterns B were provided with
different sizes (areas) and different heights.
[0047] Combinations that provide good results and specifically the
results of the examination of examples according to the present
invention are summarized in FIG. 10. Combinations that fail to
provide good results and specifically the results of the
examination of comparative examples are summarized in FIG. 11.
Regarding the results of the examination shown in FIGS. 10 and 11,
the evaluation of the gloss and matte effect was performed by
visually observing the presence or absence of the gloss-lowering
effect before and after the molding of the recess-and-protrusion
pattern. The evaluation in a scratch resistance test was performed
by scratching the surface with the nail 10 times in a reciprocating
manner and then visually observing the presence or absence of a
change in gloss on the scratched surface. The evaluation of
unpleasant noise during the scratching was performed by checking
the presence or absence of high-frequency frictional noise during
the scratching with the nail. Regarding the results of the
evaluation shown in FIGS. 10 and 11, the bullseye symbol
.circle-w/dot. and the circle symbol .smallcircle. indicate good
results at acceptable levels, in which the former indicates a
result better than that indicated by the latter. The double cross
symbol xx and the cross symbol x indicate poor results at
unacceptable levels, in which the former indicates a result worse
than that indicated by the latter. Moreover, the symbol + or -
indicate that the result is slightly better or worse than indicated
by the corresponding symbol.
[0048] The results in FIGS. 10 and 11 show the following. Regarding
patterns A, when the pitch d is equal to or greater than 300 .mu.m
(d.gtoreq.300 .mu.m), the parallel line group pattern is so thick
as to be clearly visible and cannot provide a practically realistic
design appearance (resulting in a fake appearance). See Example 3
and Comparative Example 3. Regarding patterns A, when the height h1
is equal to or less than 5 .mu.m (h1.ltoreq.5 .mu.m), the
gloss-lowering effect cannot be obtained, and the resulting gloss
is at the same level as that obtained with a pattern having no
parallel line group. See Example 4 and Comparative Example 4.
Regarding patterns B, when the size s is equal to or less than 0.01
mm.sup.2 (s.ltoreq.0.01 mm.sup.2), the added area is not enough to
keep the pattern A portion scratch-resistant, and the scratch
resistance is degraded. See Example 6 and Comparative Example 5.
Regarding patterns B, when the height h2 is equal to or less than
20 .mu.m (h2.ltoreq.20 .mu.m), the added recesses and protrusions
are not enough to keep the pattern A portion scratch-resistant, and
the scratch resistance is degraded. Regarding patterns A, the
scratch resistance is better when the flat portion is located at an
uppermost position (pattern No. 5) than when the flat portion is
located at a lowermost position (pattern No. 4). Regrading patterns
B, there is no difference in performance between a pearskin-like
texture (pattern No. 6) and a random texture (pattern No. 7).
[0049] In view of the results shown above, the linear
recess-and-protrusion pattern portion 11 preferably has grooves
arranged at pitches of 240 .mu.m or less. The protrusion pattern
portions 13 each preferably have an area of 0.02 mm.sup.2 or more.
Regarding patterns A, the height is preferably 5 .mu.m or more. The
protrusion pattern portions 13 each preferably have a height of 20
.mu.m or more.
[0050] Moreover, patterns B (protrusion pattern portions 13) are
expected to be effective in preventing damage by scratching, for
example, which would otherwise occur if the user scratches the
linear recess-and-protrusion pattern portion 11 when touching by
hand. The space between each pair of protrusion pattern portions 13
is an important feature for effectively preventing the damage to
the linear recess-and-protrusion pattern portion 11. If the space
between the protrusion pattern portions 13 is too wide, the user
may fail to touch the protrusion pattern portion 13 with a finger
or the like and more easily touch the linear recess-and-protrusion
pattern portion 11. Even in view of such a problem, if the
protrusion pattern portions 13 are too densely arranged, the
intended beautiful design may fail to be provided. Since the
individual protrusion pattern portions 13 are randomly arranged,
there may be a variety of intervals between them. When a certain
protrusion is selected from the protrusion pattern portions 13, the
distance between the protrusion and another protrusion closest to
the protrusion may be called a shortest distance. There are many
shortest distances, among which the maximum one may be called the
maximum shortest distance. The maximum shortest distance may be set
in an appropriate range so that the protrusion pattern portions 13
can be arranged at an appropriate density, which is not too low and
not too high. When the main purpose is to prevent touching by hand
from causing damage, for example, the maximum shortest distance may
be set in the range of 2 mm or more and 10 mm or less.
[0051] As described above, according to this embodiment, the
protrusion pattern portions 13 are provided to appropriately
reinforce the decorative sheet without degrading the function of
the linear recess-and-protrusion pattern portion 11. This
embodiment also makes it possible to provide a beautiful design
with no adverse effect on the intended gloss and matte
appearance.
Second Embodiment
[0052] FIG. 12 is a perspective view showing, in an enlarged
manner, a portion of a decorative sheet 1B according to a second
embodiment of the present invention. FIG. 13 is a cross-sectional
view of the decorative sheet 1B along a cutting plane perpendicular
to the sheet surface. In the first embodiment, the smooth pattern
portion 12 has a height equal to the height of the protrusions of
the linear recess-and-protrusion pattern portion 11. On the other
hand, in the decorative sheet 1B according to the second
embodiment, the level of the smooth pattern portion 12 is the same
as the level of the bottom surface of the grooves of the linear
recess-and-protrusion pattern portion 11. Even when the decorative
sheet is configured in this manner, the protrusion pattern portions
13 are sufficiently effective in reinforcing the linear
recess-and-protrusion pattern portion 11.
Third Embodiment
[0053] FIG. 14 is a perspective view showing, in an enlarged
manner, a portion of a decorative sheet 1C according to a third
embodiment of the present invention. FIG. 15 is a cross-sectional
view of the decorative sheet 1C along a cutting plane perpendicular
to the sheet surface. In the first embodiment, the smooth pattern
portion 12 has a height equal to the height of the protrusions of
the linear recess-and-protrusion pattern portion 11. On the other
hand, in the decorative sheet 1C according to the third embodiment,
the smooth pattern portion 12 has a height greater than the height
of the protrusions of the linear recess-and-protrusion pattern
portion 11. Moreover, in the decorative sheet 1C according to the
third embodiment, the protrusion pattern portions 13 have a height
equal to the height of the smooth pattern portion 12. Even when the
decorative sheet is configured in this manner, the protrusion
pattern portions 13 are sufficiently effective in reinforcing the
linear recess-and-protrusion pattern portion 11.
Fourth Embodiment
[0054] FIG. 16 is a perspective view showing, in an enlarged
manner, a portion of a decorative sheet 1D according to a fourth
embodiment of the present invention. FIG. 17 is a cross-sectional
view of the decorative sheet 1D along a cutting plane perpendicular
to the sheet surface. In the first embodiment, the smooth pattern
portion 12 has a height equal to the height of the protrusions of
the linear recess-and-protrusion pattern portion 11. On the other
hand, in the decorative sheet 1D according to the fourth
embodiment, the smooth pattern portion 12 has a height greater than
the height of the protrusions of the linear recess-and-protrusion
pattern portion 11 as in the third embodiment. In the decorative
sheet 1D according to the fourth embodiment, the protrusion pattern
portions 13 also have a height greater than the height of the
smooth pattern portion 12. Even when the decorative sheet is
configured in this manner, the protrusion pattern portions 13 are
sufficiently effective in reinforcing the linear
recess-and-protrusion pattern portion 11.
Modifications
[0055] The embodiments described above are not intended to limit
the present invention and may be altered or modified in various
ways within the scope of the present invention.
[0056] (1) Each embodiment shows an example in which the linear
recess-and-protrusion pattern portion 11 has grooves arranged in
parallel to one another, and the grooves has a plan view pattern
showing a group of parallel straight lines. Such features are
non-limiting, and alternatively, for example, the grooves may be
arranged in a curved line pattern or a combined pattern of straight
and curved lines in plan view.
[0057] (2) Each embodiment shows an example in which the base
material and the print layer are heat laminated with the resin
layer. Such a feature is non-limiting, and alternatively, for
example, a photocurable resin may be used to form the
recess-and-protrusion pattern portion on the base material and the
print layer. The multilayer structure may also be modified, for
example, by adding another layer, such as a reflective layer, or by
omitting the base material or the print layer.
[0058] (3) Each embodiment shows an example having the smooth
pattern portion 12. Such a feature is non-limiting, and, for
example, an alternative embodiment may be provided without the
smooth pattern portion 12.
[0059] Although not described in detail, any appropriate
combination of the first, second, and third embodiments and
modifications thereof may be provided. It will be understood that
the embodiments described above are not intended to limit the
present invention.
[0060] (4) Each embodiment shows an example in which the contour
shapes of the linear recess-and-protrusion pattern portion 11, the
smooth pattern portion 12, and the protrusion pattern portions 13,
and the patterned layer 3 reproduce the plan view pattern of
various polygonal mineral single crystals arranged in a
cross-section of a granite plate. Such a feature is non-limiting,
and alternatively, for example, the contour shapes of the linear
recess-and-protrusion pattern portion 11, the smooth pattern
portion 12, and the protrusion pattern portions 13, and the
patterned layer 3 may produce other appearances of plan view
patterns, such as those shown below.
(4-1) Patterns of various mineral components in a cross-section of
a plate of marble, onyx, travertine, or the like. (4-2) Wood grain
patterns on the surface of an autumn wood portion, a spring wood
portion, a light portion, a wood surface portion, or the like of a
plate of any wood, such as pine, cedar, or zelkova. (4-3) Plan view
patterns of fabrics or knits of fibers of silk, cotton, or hemp, or
various synthetic fibers. (4-4) Artificially designed patterns,
such as various geometrical figures or letters arranged in a
plane.
[0061] (5) Each embodiment shows an example of a pictorial
pattern-printed decorative sheet having a multilayer structure of
the resin layer 4 and the base material 2. Such a feature is
non-limiting, and alternatively, for example, the sheet may have a
monolayer structure without the resin layer 4, which functions as a
protective layer, if the pictorial pattern is omitted.
Alternatively, the sheet may have a structure of three or more
layers. The multilayer structure may be formed with or without an
adhesive layer. For example, dry lamination using an adhesive layer
may be performed, or heat lamination may be performed with no
adhesive layer.
[0062] (6) In each embodiment, the protrusion pattern portions 13
have a flat top as shown in the drawings. FIG. 18 is a view showing
a modified form of the top of the protrusion pattern portion 13.
For example, a decorative sheet 1E shown in FIG. 18 may be
provided, in which the top of the protrusion pattern portion 13 is
shaped in a recess-and-protrusion pattern corresponding to the
linear recess-and-protrusion pattern portion 11. When the structure
shown in FIG. 18 is formed, an etching process may be used in the
mold forming step so that the mold can be easily formed in some
cases.
[0063] (7) For easy understanding, each embodiment has been
described with reference to the drawing showing that only the resin
layer 4 has the recess-and-protrusion pattern. Such a feature is
non-limiting, and alternatively, for example, the top and bottom
surfaces of the decorative sheet may each have the
recess-and-protrusion pattern. FIG. 19 is a view showing an example
of a decorative sheet also having the recess-and-protrusion pattern
on its bottom side. A decorative sheet 1F shown in FIG. 19 may be
provided in which its bottom side (the lower side in FIG. 19) has
recesses corresponding to the significantly protruding portions on
its top side.
[0064] Alternatively, the top and bottom surfaces may each have all
recess-and-protrusion patterns.
EXPLANATION OF REFERENCE NUMERALS
[0065] 1, 1B, 1C, 1D, 1E, 1F: Decorative sheet [0066] 2: Base
material [0067] 3: Patterned layer [0068] 4: Resin layer [0069] 11:
Linear recess-and-protrusion pattern portion [0070] 12: Smooth
pattern portion [0071] 13: Protrusion pattern portion [0072] 21:
Large diameter roller [0073] 22: Heater [0074] 23: Mold roller
[0075] 24: Die roller
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